Last Direct Current Power-User Goes To A.C.

Press, Volume XCVII, Issue 28701, 26 September 1958, Page 8

Last Direct Current Power-User Goes To A.C.

When a retail shop this week transferred the power for its lift from direct current to alternating current, the Municipal Electricity Department was able to shut down a machine which had been running since 1913. In doing so it marked the end of an era—D.C., the system used by all Christchurch consumers in the early days of electricity. had disappeared from the city. Over the last few years there have been very few consumers taking direct current, and the department in recent years has done its best to encourage them to change over to A.C.. for it was quite uneconomic to run machines at the Armagh street substation simply to supply a few lifts In 1902, the City Council decided to install two 100 kw D.C. generators, and steam was obtained from burning the city’s rubbish in a destructor, the tall chimney of which was a city landmark. On July 25, 1903. the municipal electricity supply was made available to the city, and as the load grew more steam engines and D.C. generators were installed. In 1914. hydro power became available from Lake Coleridge, and it was alternating current, so that some form of converting equipment wa» neryswry to enable supplies to be-.OWTunued to the many consumers then on D.C. Two 50u kw rotary converters were bought from Britain in Mil in preparation for the task They have operated ever since, Partiealarly good service .yo requiring a minimum of maintenance. One of the ma-

chines was scrapped earlier this year when only three lifts remained to take D.C. power, and now that its task has ended the other machine will also be broken up as there is no use for it anywhere.

Shortly after the first A.C. supply was received from Lake Coleridge, the department tried to eliminate as much D.C. as possible, and by 1920 a large part of the load had been changed over at little cost to the council. The department used to pay the cost of any new wiring required, supply and install the A.C. motors where necessary and take over the D.C. motors which it was able to sell at good prices in the North Island and Australia